Producing cyclohexene or alkylcyclohexene

Abstract

Benzene or an alkylbenzene is reacted with hydrogen and an alkali metal such as potassium in the presence of a polyamine to produce cyclohexene or alkylcyclohexene and alkali metal hydride. The polyamine contains only C, N and H and has at least three nitrogens. Each nitrogen is linked to three carbons and each carbon bridge is at least two methylenes long. Representative polyamines are hexamethyl hexacyclen, hexamethyl triethylene tetraamine, tris(2-dimethylamino ethyl)amine and octamethyl pentaethylene hexamine. Cyclohexene is produced at high ratios with respect to cyclohexane.

What is claimed is: 
     
       1. A process for the selective hydrogenation of aromatic hydrocarbons which comprises reacting a liquid aromatic hydrocarbon selected from the group consisting of benzene and alkylbenzenes containing 7-10 carbons with an alkali metal selected from the group consisting of sodium, potassium and mixtures thereof, and with hydrogen in the presence of a polyamine containing only C, N and H, with at least 3 nitrogens, each nitrogen being linked to three carbons and each carbon bridge between nitrogens being at least two methylene units long, under conditions producing cyclohexene or alkylcyclohexene. 
     
     
       2. The method of claim 1 wherein said alkali metal is potassium. 
     
     
       3. The method of claim 1 wherein said alkali metal is a mixture of sodium and potassium. 
     
     
       4. The method of claim 1 or 2 or 3 wherein said aromatic hydrocarbon is benzene. 
     
     
       5. The method of claim 4 wherein said polyamine has at least 4 nitrogens, the carbon bridges between nitrogens are ethylene and the remaining alkyls are methyl or ethyl. 
     
     
       6. The method of claim 5 wherein said polyamine is ##STR3## wherein n is an integer between 3 and 6, inclusive. 
     
     
       7. The method of claim 6 wherein n is 3. 
     
     
       8. The method of claim 5 wherein said polyamine is N[CH 2  CH 2  N(CH 3 ) 2  ] 3 . 
     
     
       9. The method of claim 5 wherein said polyamine is a cyclic amine of the formula: ##STR4## wherein n is an integer between 5 and 8, inclusive. 
     
     
       10. The method of claim 9 wherein n is 6.